Since multi-story buildings were first built, there has been a need for dependable access for fire fighters as well as for evacuation of the occupants thereof in case of fire and other emergencies.
Fixed exterior fire escapes have been commonly required on smaller buildings such as three or four stories and have even been installed on buildings as high as seven or eight stories. On taller buildings, almost universally fire proof stair wells have been required even though these commonly fill with smoke during a major fire.
In an effort to overcome to limitations of stair-type exterior fire escapes and fire proof stair wells on what is commonly referred to as high rise buildings which can go to a hundred or more floors or stories, exterior elevators have been developed and several of these have even been patented.
Several of these include exterior elevator shafts which are subject to becoming smoke filled as well as exterior elevators mounted on rails or the like, some of which can be fitted after the emergency arises.
These various exterior evacuation or fire escape systems are unsightly at best and are of limited utility.